1. Technical Field
The present disclosure relates to an image display system including a transparent screen.
2. Description of the Related Art
Recent years have seen some proposals for a transparent screen that displays an image by diffusely reflecting or diffusely transmitting image light projected by a projector while transmitting background light. For example, an image display system including such a transparent screen uses a window of a high-rise building as the transparent screen on which the projected image is superimposed on a night view and displayed, or presents an image as if it were displayed in the air at a live performance or the like. As noted above, the transparent screen is expected to serve as a key device for realizing a new image expression using the projector.
One proposed transparent screen of a transmission type adopts a system of allowing image observation by dispersing a trace amount of specific diffusing particulates in a transparent body to greatly diffuse part of image light as well as allowing background observation by transmitting background light rectilinearly (see Japanese Patent No. 5214577).
Furthermore, since the diffusely transmitted light is partially reflected by an interface between a back surface of the transparent screen and the air, the structure obtained by dispersing a trace amount of the diffusing particulates in the transparent body can also be used as a transparent screen of a reflection type.
Moreover, as a transparent screen of a reflection type, proposed is a screen that is obtained by forming on a plurality of protrusions a selective reflection layer that selectively reflects right circularly polarized laser light or left circularly polarized laser light at a specific wavelength, and coating a surface of the selective reflection layer with a transparent material (see Japanese Unexamined Patent Application Publication No. 2014-71250). Additionally, another proposed transparent screen of a reflection type is a screen obtained by providing a light reflecting region in a portion of a transparent base so as to partially reflect light (see Japanese Unexamined Patent Application Publication No. 2006-119489).
With the use of the transmission-type or reflection-type transparent screen described above, an observer can both observe a background and enjoy an image.